Recently, much research has been conducted for safe driving of a vehicle driver. That is, an electronic device such as a navigation device guides a destination when a vehicle is operated or re-searches and guides a destination when the vehicle departs from a route to the destination, using global positioning system (GPS) position information and various sensors based on road map information.
However, conventional GPS devices have a positional deviation of 20 to 30 m. Thus, the conventional GPS devices cannot precisely recognize a traveling lane. Therefore, although a vehicle departs from a route to a destination, the conventional GPS devices cannot immediately guide the destination. When a driver selects a wrong route such that the vehicle departs from the route to the destination, the vehicle must return after traveling a considerably long distance or make a detour to another route.
A recently-developed differential GPS (DGPS) device has a positional deviation of about 1 m. Since general roads have a width of 3 to 5 m, line information recognized by the DGPS device may be used to guide a route departure.
However, the DGPS device is very expensive. Thus, when the DGPS device is mounted in a vehicle, the price of the vehicle rapidly increases. That is, there is a fundamental limit in mounting an autonomous navigation system using the DGPS device in a vehicle.